Pomona scientist played major role in giant panda's birth of twins

When Lun Lun the giant panda gave birth to the first set of twins born in the United States in 26 years at Zoo Atlanta on Monday night, it was cigars all around.

The celebration included one proud papa at the Western University of Health Sciences in Pomona: Assistant Professor of Physiology David Kersey.

Without Kersey, who figured out the precise ovulation time for Lun Lun and helped administer two sequential rounds of artificial insemination, there would be no panda cubs.

"It is awesome. Fantastic," said Kersey on Wednesday at his laboratory, describing the feeling when he learned Lun Lun was expecting and when the 15-year-old black-and-white bear had given birth to twins no less, something no one had anticipated.

This was Kersey's fourth successful artificial insemination procedure with giant pandas in captivity out of four attempts, all in Atlanta and all with Lun Lun. He's batting 1.000 in a field with only a 50 percent success rate.

In a short 10 years, Kersey has become the leading expert on artificial insemination of the iconic bear species from China. His research on hormone levels in both male and female giant pandas, and more recently on the quirky ovulation cycles of the female panda, has led to innovative methods taught to breeders in the United States and China.

Kersey has set up endocrinology labs directly in China's two main breeding facilities, in Chengdu and Bifengxia. A colleague from Bifengxia Panda Base will visit Kersey in the fall at the Pomona-based university to compare results, he said.

"Whenever you are doing these artificial inseminations, you wonder 'Am I doing it right? Did we time it right? Did we put the semen in the right place? Was it of the best quality.' Up until that point you are always second guessing. Then when you find out it took, well it is like," he said, blowing out a puff of air as a sign of pure relief.

Kersey had the zookeepers in Zoo Atlanta send him Lun Lun's urine samples, which he analyzed in his lab in Pomona for ovulation hormones. Incredibly, he could pinpoint a 40-hour window when Lun Lun would be most susceptible to the procedure. He hopped on a plane for Atlanta and after further urine analysis, determined it was go time.

"I was running samples day and night. I don't think I slept much," he said. "My colleague from the Smithsonian National Zoo and I looked at the data and said we need to do this now. We were talking about a 40-hour window -- at max -- then that is the end of it," Kersey said.

Wanting to keep things as natural as possible, Zoo Atlanta officials and Kersey, along with Copper Aitken-Palmer of the Smithsonian, watched as Yang Yang, the father of the pair's other offspring, Mei Lan, 6, Xi Lan, 4, and Po, 2 was brought into her enclosure. The male and female panda were separated by what is called a "howdy gate," which allows the scientists to gauge mating behavior. The gate is there to separate a male and female who don't get along and can end up fighting each other with disastrous results.

But after 15 years of living together, Yang Yang had apparently lost interest.

"They rebuked each other. That is the best way to put it," Kersey said. "We were there, we were looking. But this wasn't happening," he said.

Quickly, Lun Lun was sedated and artificially inseminated. First, before midnight on March 21, with a batch of two-week old frozen semen and then at 7 a.m. March 22 with a fresh sample.

Since there is no pregnancy test for a giant panda, the next three months was a waiting game for the scientists. Kersey's research on female panda hormones and ovulation windows was critical to Lun Lun achieving a pregnancy. But an ultrasound on June 30 only detected one embryonic heartbeat, so Monday's twin births shocked zoologists around the world.

"It was a surprise to them," Kersey said. He couldn't recall another birth of twin giant pandas in the United States, where there are only four breeding pairs. In China, with 300 pandas in captivity and 1,600 total, twins are much more common, he said.

Zoo Atlanta officials and an expert from Chengdu Breeding Base will give Lun Lun one cub at a time to nurse, then swap out the other one, and repeat the pattern for several months. In the wild, giant pandas raise one cub at a time, often leaving the other to die, according to Dwight Lawson, deputy director of Zoo Atlanta. "It is physically difficult for the mother panda to manipulate more than one cub," Lawson said.

The cubs are very small, only 1/900th the size of the adult panda which can reach 200 pounds. The cubs are the size of sticks of butter, are pink in color and hairless. But they will double in size in a week, he said and begin showing color patterns shortly. The public can see the cubs in the fall, the zoo announced.

Chinese tradition dictates the cubs receive a name when they turn 100 days old, Kersey said. He didn't have any suggestions, saying that should be left up to the public.

"It's fun to get the public involved," he said. "It helps if the public feels they have a commitment to them," he said.

Kersey has begun new studies on how to breed snow leopards, which are indigenous to central Asia and also an endangered species.

"I am trying to take the work I've done with the giant pandas and use if for conservation of other species," he said.